A problem exists when driving a flat belt with a drive roller when contamination is present. Water, dust, or mud-like material can reduce the coefficient of friction between the drive roller and the flat belt. Particularly, problematic with agricultural balers is an accumulation of wet organic material (wet silage) which creates a ‘slime’ layer between the drive roller and the flat belt that can lead to extensive slipping. This problem is aggravated by the fact that the wet organic material also has a tendency to adhere to the belts and rollers.
In the past it has been recognized that it is necessary to take actions in order to reduce or eliminate such accumulations of extraneous material to maintain a positive drive. It has, for example, been known to use lagging on drive rollers in order to increase the friction between the flat belt and the lagging surface. Known lagging types used for round agricultural baler applications are smooth or finely grooved circumferentially so as to allow a path for water or other accumulations to be displaced during operation, thus preventing large decreases in the friction coefficient during operation. However, these designs are only partially effective, as measured decreases are apparent between clean and contaminated samples.
Accordingly, there is a clear need in the art for an improved drive roller, particularly for agricultural balers, that is effective to remove extraneous material from the drive roller-belt interface so as to consistently maintain the coefficient of friction necessary to maintain a positive drive.